Upon closer study, a great deal more can be uncovered, however it completely depends on the manner that the observer wishes to learn, and what technology is used. The inhabitants are mostly oblivious of the matters outside of their planet.
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Visual Study
Slightly more than half of the planet is covered by water, the landmasses shaping two major continents and one pseudo-continent. Planet covers every basic type of climate biomes, the axel tilt causing winter and summer seasons on northern and southern hemispheres. There are no polar ice caps.
Electricy is widespread and in use on every continent. According to lights: every town, city and village is part of electric grid. There's plenty of large cities spotting the globe, multiple roads and railroads sneaking between them. There are occasional lights of planes passing by, both in formations of multiple, and invidual ones flying form city to another. Rough estimate for population on the whole globe would be over two billion. With large enough magnifications, large battleships can be seen sailing on water, some being as massive as common spaceships (500 meters / 550 yards). There's also a continent splitting wall between two nations, both sides having multiple gun emplacements, pillboxes and fortresses along it, making a grim scar into the other vice mostly lushy planet.
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Radiowaves
On the southern continent, at western end of it, there's only strong state and socialist propaganda on the air, along with multiple military channels with weak encryptions. Most of the content on these radioshows are focussed on positive feedback, highlighting the workforce and not the actual leaders of the nation. There's suprisingly little animosity against their own people and other nations, excluding their main rival. Nation's name is swiftly found: Tomup. The leadership seems to be consisting of multiple inviduals: The Council of Equals. Military channels are mostly dotted with short relayed patrols, reports or tests, leaving the channels with mostly dead air.
On the eastern part of the same continent, there's mostly state owned news channels, which play music on downtimes, with badly made state funded entertainment programs. Over all, the radio seems to lack propaganda aspects, but it's service is lacking in quality. Nation is called Tossa, and it seemingly has a monarchist leader know as The Empress (without an actual name). On the military side, the whole area is a mess, radar stations are tracking the border and coastal regions, the military channels are having decrypted messages constantly, the large navies updating their status and location regularly. Even smallest artillery crews by the border are reporting every six hours and informing next movement location if there's one, leaving any advanced civilization with code cracking abilities and decryption skills, with almost complete map of their military personel.
On the northern continent, the north, middle and eastern part of it, there's yet another nation. The radiowaves are full of commercials, with occasional extremely catchy songs here and there to draw in the interest of the people. There seems to be no rules at all for any of the stations, some doing nothing more than commercials from morning to evening, some telling stories of fiction and some blatantly giving out conspiracy theories as truth. Some of the commercials for corporations are dissimilar from propaganda. There's practically a radio station for anything, even for old lady telling how weather has been for past 60 years, day by day. The military channels are barely decrypted, and the channels are full of chatter, bigger fish stories and eager talks about the next firing range trainings. It can be really difficult to find the name of the nation, but after a lot of effort it can be found, it being Tarofir.
At western and south side of the same continent, there's few radio stations, all of them broadcasting religious agenda from different aspects. Some are reading religious texts, spoken by one of the religious heads, some are broadcasting children stories with applied religious values, and some simply preach of the virtues of their citizens. It wouldn't take long to pick up the name of the nation, that being Tanven, lead by High-Cardinal. Military channels are, non-existant.
Lastly on the pseudo continent on the northern hemisphere, there's one last nation. The airwaves are mostly clean, there's few goverment funded stations sharing news in neutral manner, science focussed talkshows and educatory channels. Along with these there's few independent radiostations, mostly broadcasting entertainment services, with poor quality. Nation's name is picked up as Tience, the leader being Director. Military channels are well encrypted (for their tech level), and mostly consist of coastal guard reports, with their weak navy trying to turn the southern factions navy ships around by diplomatical means before they enter their waters. The whole island is dotted by radar sites, some even airborne.

((Sadly image quality is extremely poor.))
There doesn't seem to be any way to find a common word the planet, the planet is called: earth, ground, country(side), soil and any equilement that simply means the very dirt beneath their feet, and not exactly a planet amongst others.
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Biological Scanners (able to bypass structures)
There's 3 billion inhabitants on the planet, the number being oddly high for it's era, which might be explainable by advances in medicinal field. Nations categorized as Tossa and Tomup have roughly a billion inhabitants, and Tarofir 500 million. Tanven has 300 million and lastly Tience has 100 million. There's plenty of different sort of domesticated and wild animals on the planet, counting to plethora of species for fauna and flora both. Most people seems to live in large cities, the rural areas being sparcely populated. There seems to be life on the two other planets in the system...
((Still new at this so if there's any advice or mistakes feel free to highlight them!))
((This is just a background detailment, so the higher tech civilization can choose it's approach, as none of the people living on the planet would notice the ship in time, making sneaking in automatic success.))


